@@ -2153,9 +2153,11 @@ static int pl022_probe(struct amba_device *adev, const struct amba_id *id)
master->auto_runtime_pm = true;
master->transfer_one_message = pl022_transfer_one_message;
master->unprepare_transfer_hardware = pl022_unprepare_transfer_hardware;
- master->rt = platform_info->rt;
master->dev.of_node = dev->of_node;
+ if (platform_info->rt)
+ master->rt_prio = MAX_RT_PRIO - 1;
+
if (platform_info->num_chipselect && platform_info->chipselects) {
for (i = 0; i < num_cs; i++)
pl022->chipselects[i] = platform_info->chipselects[i];
@@ -1286,7 +1286,7 @@ static void spi_pump_messages(struct kthread_work *work)
static int spi_init_queue(struct spi_master *master)
{
- struct sched_param param = { .sched_priority = MAX_RT_PRIO - 1 };
+ struct sched_param param = { .sched_priority = master->rt_prio };
master->running = false;
master->busy = false;
@@ -1308,9 +1308,10 @@ static int spi_init_queue(struct spi_master *master)
* request and the scheduling of the message pump thread. Without this
* setting the message pump thread will remain at default priority.
*/
- if (master->rt) {
+ if (master->rt_prio >= 0 && master->rt_prio < MAX_RT_PRIO) {
dev_info(&master->dev,
- "will run message pump with realtime priority\n");
+ "will run message pump with realtime priority %d\n",
+ master->rt_prio);
sched_setscheduler(master->kworker_task, SCHED_FIFO, ¶m);
}
@@ -1862,6 +1863,7 @@ struct spi_master *spi_alloc_master(struct device *dev, unsigned size)
device_initialize(&master->dev);
master->bus_num = -1;
+ master->rt_prio = -1;
master->num_chipselect = 1;
master->dev.class = &spi_master_class;
master->dev.parent = dev;
@@ -341,11 +341,11 @@ static inline void spi_unregister_driver(struct spi_driver *sdrv)
* @xfer_completion: used by core transfer_one_message()
* @busy: message pump is busy
* @running: message pump is running
- * @rt: whether this queue is set to run as a realtime task
* @auto_runtime_pm: the core should ensure a runtime PM reference is held
* while the hardware is prepared, using the parent
* device for the spidev
* @max_dma_len: Maximum length of a DMA transfer for the device.
+ * @rt_prio: realtime priority of the message pump (-1 to use default prio)
* @prepare_transfer_hardware: a message will soon arrive from the queue
* so the subsystem requests the driver to prepare the transfer hardware
* by issuing this call
@@ -522,12 +522,12 @@ struct spi_master {
bool idling;
bool busy;
bool running;
- bool rt;
bool auto_runtime_pm;
bool cur_msg_prepared;
bool cur_msg_mapped;
struct completion xfer_completion;
size_t max_dma_len;
+ int rt_prio;
int (*prepare_transfer_hardware)(struct spi_master *master);
int (*transfer_one_message)(struct spi_master *master,
Commit 14af60b6fb3b ("spi/pl022: Add high priority message pump support") extended the pl022 driver to optionally run the message pump kworker thread with realtime priority, subject to a bool set by the platform. Commit ffbbdd21329f ("spi: create a message queueing infrastructure") moved a large portion of pl022 to generic code, making the realtime priority support available to other drivers. However the priority is set to MAX_RT_PRIO - 1, higher than most IRQs and identical to the CPU timer clock threads. This seems excessive so make the priority configurable. Cc: Mark Brown <broonie@kernel.org> Cc: Chris Blair <chris.blair@stericsson.com> Cc: Linus Walleij <linus.walleij@linaro.org> Cc: Mathias Duckeck <m.duckeck@kunbus.de> Signed-off-by: Lukas Wunner <lukas@wunner.de> --- drivers/spi/spi-pl022.c | 4 +++- drivers/spi/spi.c | 8 +++++--- include/linux/spi/spi.h | 4 ++-- 3 files changed, 10 insertions(+), 6 deletions(-)